Processes for preparing polymer products such as polyurethanes are known in the art. For example, traditional polyurethanes are synthesized by reacting an isocyanate with a polyol. Typical polyurethane foam formation via isocyanates is also known in the art. However, isocyanate-based polyurethane synthesis methods are known to have environmental, health and safety concerns and there is a growing trend in the industry to discover alternative chemistries to alleviate these concerns. Typically, isocyanate-based polyurethanes may be used, for example, in end-use applications such as spray foams.
It is also known to use a 1-12 part by weight addition of a mono alkyl cyclic carbonate as a stabilizer in traditional isocyanate foams; or as a blowing agent in traditional foam formulations. However, cyclic carbonate-amine foams per se are not known or taught in the prior art. In addition, nothing in the prior art teaches a divinylarene dioxide cyclic carbonate which can react at room temperature (25° C.) and produce an exotherm sufficient for room temperature cure and foam formation.
The polymerization of cyclic carbonates with amines is a known alternative to generating a related type of polyurethane network termed a poly(hydroxyurethane). But poly(hydroxyurethane)s derived from cyclic carbonates and amines suffer from poorer reactivity when compared to the aforementioned isocyanate chemistries. In addition, certain cyclic carbonate monomers, such as those derived from bisphenol A epoxy resins, are solids at room temperature, rendering processing difficult. Other cyclic carbonate monomers, such as those based on poly ether epoxy resins, remain liquid at room temperature but are not capable of room temperature cure or foam formation. In view of the above issues regarding cyclic carbonates with amines, foaming utilizing a cyclic carbonate monomer has heretofore not been disclosed in the prior art.
Heretofore, it known to prepare poly(hydroxyurethane)s by reacting a cyclic carbonate from an epoxy resin (e.g. bisphenol A diglycidyl ether) with a polyamine (e.g. diethylenetriamine, ethylene diamine). The resulting polymers are mixed with other polyamines, pigments and fillers in an aqueous solution with a commercial aqueous epoxy resin (e.g. Beckopox, VEP 2385) to form an automotive coating. The poly(hydroxyurethane) polymer requires heat to cure and is created in solvent prior to incorporation with the aqueous epoxy resin. Similar materials utilizing a tricyclic carbonate (e.g. trimethylolpropanetriglycidyl ether converted to the tri cyclic carbonate) as a crosslinker with a primary amine functional resin for electro deposition coatings have also been disclosed in the art.
Also known in the art is a method for using amine-terminated oligomers and cyclic carbonate/epoxy-terminated oligomers to create a hybrid network of urethane/epoxy-amine groups.
The prior art generally requires heated curing (curing temperatures generally between 70° C. and 120° C.) to utilize cyclic carbonate-amine poly(hydroxyurethane) networks in traditional coating applications. Many examples also require solvent-based polymerizations because many traditional epoxy resins will solidify as the percentage of epoxy groups converted to cyclic carbonate groups approaches 100% (e.g. DER™ 383 begins to solidify as the bulk cyclic carbonate concentration exceeds 70%). Epoxy resins that remain liquids at room temperature after 100% conversion to the cyclic carbonate (e.g. DER 736) do not produce an exotherm when reacted with amines preventing room temperature cure or foam formation.